For the purpose of defecting wiring faults in capacitive sensors such as knock sensors, an existing solution, described, notably, in patent FR 2 912 814, takes the form of a method by which:                a periodic reference signal is applied to the terminals of the capacitive sensor by means of a periodic square signal generator permanently connected to said capacitive sensor,        the capacitance at the terminals of the capacitive sensor is measured,        and the measured capacitance is compared with a nominal capacitance.        
In practice, this technique has been shown to provide reliable detection of wiring faults of the short-circuit and open-circuit types.
However, with this technique each capacitive sensor and its acquisition interface are subject to constraints relating to the generation and routing of a periodic signal.